Tests of Relations

Question 1

Which one of these questions would we not use a test of relations to find out?
1. What is the relationship between cups of coffee consumed per day and test scores?
2. Are test scores higher when more coffee is consumed?
3. Is there a difference in test scores between the group that no coffee per day vs the group that had 2 cups per day?
4. Can coffee consumed be used to predict test scores?

Answer 1

3

Question 2

A correlation does not allow for statements on:

Answer 2

cause and effect

Question 3

what are the 2 mechanisms for interpretation regarding correlation?

Answer 3

scatter plots with correlation line
correlation coefficient (r)

Question 4

The higher correlation and correlation coefficients, the closer the data points to the:

Answer 4

line of best fit

Question 5

As one variable increases, the other variable increases. This is a __________ relationship.

Answer 5

direct

Question 6

as one variable decreases, the other variable increases. This is a ___________ relationship.

Answer 6

indirect

Question 7

Test of relations for ordinal and ordinal?

Answer 7

spearmans rank

Question 8

test of relations for continuous and continuous?

Answer 8

pearsons

Question 9

test of relations for continuous and categorical?

Answer 9

point biserial

Question 10

test of relations for categorical and categorical?

Answer 10

phi correlation

Question 11

what do we use to interpet a correlation coefficient?

Answer 11

portney and watkins

Question 12

what is the portney and watkins correlation coefficient scale?

Answer 12

little to no relationship - 0 - .25
fair - .25 - .5
moderate -.5 - .75
strong -.75 - 1.00

Question 13

coefficient precautions include:

Answer 13

1. it is a measure of linear relationship only
2. interpretation is subjective
3. outliers can impact results
4. does not give any insight into comparison or causation

Question 14

what are the 2 mechanisms for interpretation of a regression?

Answer 14

scatter plots with regression line
coefficient of determination (R2)

Question 15

What is used, a linear regression or a logistic regression, when Y is continuous?

Answer 15

linear regression

Question 16

What are the 3 major goals of linear regression statistical analysis?

Answer 16

1. Calculate R2 to analyze how confidently observed differences in Y can be explained by a difference X.
2. Calculate the P value to determine if the R2 value is statistically significant
3. Use the line to predict the value of one variable from another.

Question 17

What is the difference between the correlation coefficient and the coefficient of determination?

Answer 17

R = correlation coefficient
R2 = coefficient of determination

Question 18

What represents the percentage of the total variance in the Y scores that can be explained by the X scores?

Answer 18

coefficient of determination.

Question 19

1 - R2 is the percentage of:

Answer 19

the total variance in Y not explained by the X scores.